Electronic communication has great potential for teaching and learning in all areas of the curriculum, but rarely is this potential realised. Students indulge in penpal exchanges or may collect and exchange data about their environment. What is needed for effective and efficient telecommunications is a theory of teaching and learning which provides a rational basis for the activities. Constructivism can provide such a theoretical grounding, suggesting that students must express their current ideas, confronting the alternative ideas held by others. They can then construct new concepts and change their attitudes and behaviours, rather than just gaining new knowledge and skills.